STAT 230 3rd Quiz

1. A null hypothesis makes a claim about a 

A. Population parameter

B. Sample statistic

C. Sample mean

D. Type II error

2. What is the level of significance?

A. Probability of a Type II error

B. Probability of a Type I error

C. z-value of 1.96

D. Beta error

3. A machine is set to fill the small size packages of M&M candies with 56 candies per bag. A sample revealed: 3 bags of 56, 2 bags of 57, 1 bag of 55, and 2 bags of 58. How many degrees of freedom are there? 

A. 9

B. 1

C. 8

D. 7

4. What are the two critical values for a two-tailed test with a 0.01 level of significance when n is large and the population standard deviation is known? 

A. Above 1.96 and below -1.96

B. Above 1.65 and below -1.65

C. Above 2.58 and below -2.58

D. Above 1.00 and below -1.00

5. What is a Type II error?

A. Accepting a false null hypothesis

B. Rejecting a false null hypothesis

C. Accepting a false alternate hypothesis

D. Rejecting a false alternate hypothesis

6. For a hypothesis test with an alternative hypothesis: µ > 6,700, where is the rejection region for the hypothesis test located? 

A. Both tails

B. Left or lower tail

C. Right or upper tail

D. Center

7. If 20 out of 50 students sampled live in a college dormitory, what is the estimated proportion of students at the University living in a dormitory? 

A. 0.20

B. 0.40

C. 0.50

D. 0.60

8. The average cost of tuition, room and board at small private liberal arts colleges is reported to be $8,500 per term, but a financial administrator believes that the average cost is higher. A study conducted using 350 small liberal arts colleges showed that the average cost per term is $8,745 with a standard deviation of $1,200. Let = 0.05. What is the p-value for this test? 

A. 0.0000

B. 0.0124

C. 0.0500

D. 0.4938

9. A hypothesis regarding the weight of newborn infants at a community hospital is that the mean is 6.6 pounds. A sample of seven infants is randomly selected and their weights at birth are recorded as 9.0, 7.3, 6.0, 8.8, 6.8, 8.4, and 6.6 pounds. What is the alternate hypothesis? 

A. µ = 6.6

B. µ ¹ 6.6

C. µ ³ 6.6

D. µ > 7.6

10. It is claimed that in a bushel of peaches, less than ten percent are defective. A sample of 400 peaches is examined and 50 are found to be defective. If a = 0.025, what will be the decision?

A. Fail to reject the null and conclude the defects are not greater than 10%

B. Reject the null and conclude the defects are not greater than 10%

C. Reject the null and conclude the defects are greater than 10%

D. Fail to reject the null and conclude the defects are not less than 10%

11. If the decision is to reject the null hypothesis of no difference between two population proportions at the 5% level of significance, what are the alternative hypothesis and rejection region? 

A. H₀: p₁ ¹ p₂; z > 1.65 and z < -1.65

B. H₀: p₁ ¹ p₂; z > 1.96 and z < -1.96

C. H₀: p₁ > p₂; z < - 1.65

D. H₀: p₁ > 2₂; z < -1.96

12. A recent study focused on the number of times men and women send a Twitter message in a day. The information is summarized below.

At the .01 significance level, is there a difference in the mean number of times men and women send a Twitter message in a day? What is the value of the test statistic for this hypothesis test? 

A. 2.668

B. 2.672

C. 2.58            For this question I accept any your answer because the question is unclear.

D. 2.40

13. Suppose we test the difference between two proportions at the 0.05 level of significance. If the z test statistic is -1.07, what is our decision? 

A. Reject the null hypothesis

B. Do not reject the null hypothesis

C. Take a larger sample

D. Reserve judgment

14. When is it appropriate to use the paired difference t-test? 

A. Four samples are compared at once

B. Any two samples are compared

C. Two independent samples are compared

D. Two dependent samples are compared

15. The results of a mathematics placement exam at two different campuses of Mercy College follow:

What is the null hypothesis if we want to test the hypothesis that the mean score on Campus 1 is higher than on Campus 2? 

A. H₀: µ₁ = 0

B. H₀: µ₂ = 0

C. H₀: µ₁ = µ₂

D. H₀: µ₁ £ µ₂

16. Accounting procedures allow a business to evaluate their inventory at LIFO (Last In First Out) or FIFO (First In First Out). A manufacturer evaluated its finished goods inventory (in $ thousands) for five products both ways. Based on the following results, is LIFO more effective in keeping the value of his inventory lower?

This example is what type of test? 

A. One sample test of means.

B. Two sample test of means.

C. Paired t-test.

D. Test of proportions.